SatSig topic:

Strange modem behaviour

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Jul 19^th, 2008 at 9:24pm

Hello good day
My modem has issues, a linkstar s2a modem less than 1 month old, locked to NSS10. Has been working well up to this afternoon. while browsing, in between, the sat led starts looses lock, and starts blinking as if it is trying to recieve synchrosize. After a while, it fast blinks and becomes steady, and then it goes again. Wondering if it is my LNB. I have tried to do some work on it by re entering my parameters. It comes up as usual, and then after a while, it goes again.
Please anyone that could be of help should do well to tell me what it could be, cos I am real worried.
Thanks

Jul 19^th, 2008 at 11:40pm

Just some ideas.

Did the hub reboot your modem a couple of times ? Ask them. They may have downloaded update software or new configuration or something.

Use command tcmp to see what is the current outlink bit error rate. This should be something like 0.0001 or less. Do tcmp many times and see how the BER varies. Does it deteriorate to something like 0.01 prior to an outage ?.

Are the LNB cable connections poor ? Waggle them and see if it induces the fault ? Are they wet ? Has it been raining ?

Are the cumulative error counts increasing at all ?

Has the antenna moved or become loose ? Is it windy ?

Was there a brief power supply outage ?

Is the modem hot and overheating ?

Did the hub have other sites fail at the same time ?

Was a transmitter used locally ? e.g. cell phone near the cables ?

Did something obstruct the beam ? People, vehicle, animal, spider, bird, aircraft, crane ?

In the spring and autumn you will get a few minutes outage on several days when the sun passes behind the satellite.

Best regards, Eric

Jul 20^th, 2008 at 6:40pm

Run "tcmp" command once the modem operates fine and once it starts to blink. Check QPSKBER. See if QPSKBER is higher during the outage. If it is, there's something with the Rx path, so go with the procedures described by Eric above. If QPSKBER stays the same, then I'd start looking towards the modem.

Before doing all that I'd also check with your teleport if they don't have problems on their side (bad weather probably?)

Jul 21^st, 2008 at 12:16am

Thanks Eric and Maxim. I have not experienced that outage again since yesterday. Still observing the modem. Thanks. I suspect my rx path. well till it occurs again (hoping it never though.)
Thanks again